Precision grinding machine



March 7, 1944.

E. c. SHUGARS PRECISION GRINDING MACHINE Filed Nov. 5, 1943 @MWMWPatented Mar. 7, 1944 UNITED STATES E ATENT OFFICE 10 Claims.

Thisv invention relates to improvements in precision grinding machines.

The. main objects of this invention are:

First, to provide a precision grinding machine which after beingadjusted for particular work may be operated by a relatively unskilledworkman for the production of precision work.

Second, to provide a precision grinder having the advantages statedwhich is very easily adjusted for precision. work.

Third, to provide a structure which may be readily adapted forembodiment in machines of different types such, for example, as lathesor grinders having head stocks provided with jaw chucks.

Fourth, to, provide a means for dressing the grinding wheel and at thesame time gauging the work for precision grinding.

Objects relating to details and economies of the invention will appearfrom the description to follow. The invention 'is defined and pointedout in the claims.

A preferred embodiment of the invention is illustrated in theaccompanying drawing, in which:

Fig. 1 is a front elevation of a structure embodying the features of myinvention, the machine parts being mainly shown by dotted lines andconventionalized.

Fig. 2 is an enlargedfragmentary sectional view on a line correspondingto line 2-2 of Fig. 1 with the grinding wheel in operative relation tothe work, the head stock and chuck on the machine being illustrated bydotted lines.

Fig. 3 is an end elevation of the work holder with the grinding wheelshaft in section, the work being indicated by dotted lines.

Fig. 4 is an enlarged fragmentary section corresponding to that of Fig.2 with the grinding wheel advanced substantially through the work intotraversing relation to the dressing tool but out of dressing relationthereto which is the relation during the initial grinding, the clearancebeing exaggerated.

Fig. 5 is a view similar to Fig. 4; showin the grinding wheel inrelation to the dressing tools at the finish or near the finish of thegrinding operation.

My present invention is readily adaptable for use in machines ofstandard types such as a lathe or grinding machine and I haveillustrated my invention as embodied in an attachment for such machines,but it should be understood that it is adapted for structural embodimentwhen the machines are manufactured. The work holder illustrated isdesigned .for cams but it will be understood that the wo k holder may bedesigned for any type or shape of work, that illustrated being designedonly for internal grinding.

In the accompanying drawing, i represents the base of a grinding machinehaving a rotating head stock 2 provided with a chuck 3 having jaws 4.These jaws are adapted to clamp the work holder designated generally bythe numeral 5. The tail stock 1 is reciprocatingly mounted and isadapted to be fed transversely of the table 8 relative to its path ofreciproca tion. The grinding wheel shaft or spindle 9 is carried by thetail stock, the grinding wheel l0 being mounted on the end of the shaft.A stop H limits the forward stroke of the tail stock.

The work holder 5 is provided with a suitable chuck for the work. thework 12 illustrated being a cam and the work holder having a recess 13in the face thereof receiving the cam, the work being clamped in thisrecess by means of the clamps l4 and the clamp adjusting screws 35. Thework holder is designed to support the work with its bore It in axialalignment With the axis of the head stock. A plurality of radiallydisposed set screws 51 coact with the clamps M in securely retaining thework. At the rear of or inner side of the work receiving recess, thework holder is provided with a bore H! of a diameter exceeding thediameter of the bore of the finished work. The tail stock isreciprocated on each stroke to carry the grinding wheel through the workand into this bore I8.

I provide a plurality of grinder wheel dressing and work gauging tools59, three being illustrated, these being disposed in radial bores 2i foradjustment therein and being secured in their adjusted positions bymeans of set screws 2!. These tools are provided with diamond points 22.The dressing tools are preferably provided with adjusting screws 23, bymeans of which they may be very accurately adjusted.

In setting up for a particular piece of work, the dressing tools. areadjusted so that their diamonds lie in a circle as is shown by dottedlines in Fig. 3. This is preferably accomplished by the use of aplug-like gauge which is the dimension of the internal surface or boreof the finished work, the plug-gauge being inserted and the dressingtools adjusted to bring their points into contacting relation to thegauge. It will be. noted that the grinding wheel is of less diameterthan the bore of the work and its axis is escentric relative to the axison which the work rotates.

In the ordinary installation, the work is driven in one direction andthe grinding wheel in the reverse direction. For example, if the work isdriven in a counter-clockwise direction the grinding wheel would bedriven in a clockwise direction. It will also be noted that only onedressing tool contacts the grinding wheel in alignment with the contactof the grinding wheel with the work.

In the accompanying drawing, I have illustrated a work holder designedfor cam-shaped work but it will be understood that the work holder maybe designed for any type or shape of work and that while I haveillustrated the diamond-pointed dressing tools, other types may be used.

In operation, the grinding wheel is moved forwardly or advanced to thework and preferably passed entirely therethrough on each strokethat is,the stop is adjusted so that when the stop is reached the grinding wheelhas passed entirely through the work and into'the dressing bore orchamber. As the dressing tools are adjusted according to the internaldiameter of the finished work, they do not contact the grinding wheel orare not in dressing relation thereto until the grinding has beenpractically completed. However, as the finish grinding point is reached,the grinding wheel comes into contact with the dressing tools on eachstroke so that the dressing cams serve as work gauges. The operator willreciprocate the grinding wheel rapidly back and forth across the workwithout the grinding wheel coming into grinding contact with the work sothat an effective gauge is provided. The last stroke also serves to trueor dress the grinding wheel for the next piece of work.

I have illustrated and described my improvements in a very simple andpractical embodiment thereof. I have not attempted to illustrate ordescribe other embodiments as it is believed that this disclosure willenable those skilled in the art to embody or adapt my invention as maybe desired.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent, is:

1. The combination with a machine of the class described including ahead stock provided with a work chuck and a reciprocable tail stockprovided with a tool chuck and with lateral feed means, of a work holderadapted for mounting in said head stock chuck and to support work to beinternally ground with its axis in alignment with the axis of the headstock, said work holder having a bore at the inner side of the work of adiameter substantially exceeding the internal diameter of the finishedwork, a plurality of diamend supporting posts provided with diamondsradially adjustable on said work holder to project into said borethereof, means for securing said posts in predetermined adjustedpositions within said bore, and a grinding wheel of less diameter thanthe internal diameter of the finished work carried by said toil stockand adapted to be reciprocated through the work in grinding relationthereto and in said bore into dressing relation with the diamondswhereby on the completion of the grinding of the work the grinding wheeldressing diamonds constitute gauges determining the internal diameter ofthe finished work.

2. The combination with a machine of the class described including ahead stock provided with a work chuck and a reciprocable tail stockprovided with a tool chuck and with lateral feed means, of a work holderadapted for mountin in said head stock chuck and to support work to beinternally ground with its axis in alignment with the axis of the headstock, a plurality of diamond supporting posts provided with diamondsadjustably mounted on said work holder at the inner side of the workchuck thereof, and a grinding wheel of less diameter than the internaldiameter of the finished work carried by said tail stock and adapted tobe reciprocated through the work in grinding relation thereto intodressing relation with the diamonds whereby on the completion of thegrinding of the work the grinding wheel dressing diamonds constitutegauges determining the internal diameter of the finished Work.

3. The combination with a machine of the class described including ahead stock provided with a work chuck and a reciprocable tail stockprovided with a tool chuck and with lateral feed means, of a work holderadapted for mounting in said head stock chuck and to support work to beinternally ground with its axis in alignment with the axis of the headstock, said work holder having a bore at the inner side of the workchuck of a diameter substantially exceeding the internal diameter of thefinished work, a plurality of grinding wheel dressing tools adjustablymounted on said work holder to pro- J'ect predetermined distances intosaid bore thereof, and a grinding wheel of less diameter than theinternal diameter of the finished Work carried by said tail stock andadapted to be reciprocated through the work into grinding re lationthereto and into dressing relation with the said dressing tools wherebyon the completion of the grinding of the work the said dressing toolsconstitute gauge determining the internal diameter of the finished work.

4. The combination in a machine of the class described, of a rotatablework holder for work to be internally ground, a plurality of grindingwheel dressing tools adjustably mounted on said work holder, and anaxially movable grinding wheel of less diameter than the internaldiameter of the finished Work and adapted to be reciprocated through theWork in grinding relation thereto and into dressing relation with thesaid dressing tools whereby on the completion of the grinding of thework the said dressing tools constitute gauges determining the internaldiameter of the finished work.

5. The combination in a machine of the class described, of a rotatablymounted work holder for work to be internally ground, said work holderhaving a bore at the inner side of the work mounted therein, said borebeing or a diameter substantially exceeding the internal diameter of thefinished work, a plurality of grinding wheel dressing tools adjustablymounted on said work holder to project into said bore thereof, and anaxially movable grinding wheel of less diameter than the internaldiameter of the finished work adapted to be reciprocated through theWork in grinding relation thereto and in said bore into coactingrelation to said dressing tools whereby on the completion of thegrinding of the work the grinding wheel dressing tools constitute gaugesdetermining the internal diameter of the finished work.

. 6. The combination in a machine of the class described, of a rotatablymounted work holder for work to be internally ground, a grinding wheeldressing tool adjustably mounted on said Work holder at the inner sideof the work supported in said work holder, and a grinding Wheel of lessdiameter than the internal diameter of the finished work adapted to bereciprocated through the work in grinding relation thereto and intocoacting relation to said dressing tool whereby on the completion of thegrinding of the work the grinding wheel dressing tool constitutes agauge determining the internal diameter of the finished work.

7. The combination in a machine of the class described, of a rotatablymounted work holder for work to be internally ground, a grinding wheeldressing tool adjustably mounted on said work holder at the rear side ofthe work carried by the work holder, and a grinding wheel of lessdiameter than the internal diameter of the finished work, said workholder and grinding wheel being relatively movable to bring th grindingwheel into grinding relation to the work and thereafter into dressingrelation to said tool,

whereby the dressing tool constitutes a gauge a limiting the grindingaction of the grinding wheel on the work.

8. The combination in a machine of the class described, of a rotatablymounted work holder, a. grinding wheel dressing tool mounted on saidwork holder at the rear side of the work carried by the work holder, anda grinding wheel, said work holder and grinding wheel being relativelymovable to bring the grinding wheel and work into grinding relation andthereafter bring the grinding wheel into dressing relation to said tool,whereby the dressing tool constitutes a gauge limiting the grindingaction of the grinding wheel on the Work.

9. The combination in a machine of the class described, of a rotatablymounted work holder, a grinding wheel, said work holder and grindingwheel being relatively movable, and a grinding wheel dressing tooladjustably mounted on said work holder at the rear of the work carriedby the work holder whereby the dressing tool may be adjusted to dressthe grinding wheel and thereby limit the action of the grinding wheel onthe work.

10. The combination in a machine of the class described, of a workholder, a grinding wheel, said work holder and grinding wheel beingrelatively movable to bring the grinding Wheel into grinding relationwith the work carried by the work holder, and a grinding wheel dressingtool adjustably mounted on the work holder at the rear, of the workcarried thereby, the relative movement of said work holder and grindingwheel being such that the grinding wheel is brought into grindingrelation with the work and thereaftermoved across said dressing toolwhereby on the completion of the grinding of the work the grinding wheelis brought into dressing relation with the grinding tool on each workstroke for limiting the grinding action of the grinding wheel on thework.

ELMER C. SHUGARS.

